Heater



FIG. 1 is a top-front perspective view of a heater showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a right view thereof, the left side being a mirror image;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a bottom-rear perspective view of a heater showing my new design.

In the drawings, the broken lines shown in the figures depict environmental subject matter only and form no part of the claimed design. 

The ornamental design for a heater, as shown and described. 